T-butyl carbocyclic substituted cumene peroxides as curing agents

ABSTRACT

PEROXIDES OF THE FORMULA   (R-PHENYL)-C(-CH3)2-O-O-C(-CH3)3   WHERE R HAS THE FORMULA C6H5-C(CH3)2-   1-CH3-CYCLOHEXYL OR 1-CH3,4-((CH3-)2-C-)CYCLOHEXYL   ARE PEROXIDES WHICH CURE POLYETHYLENE AND OTHER POLYMERS AND HAVE ODOR-FREE, NON-BLOOMING AND NON-SCORCHING PROPERTIES.

United States Patent Oflice 3,584,057 t-BUTYL CARBOCYCLIC SUBSTITUTED CUMENE PEROXIDES AS CURING AGENTS Frederick G. Schappell, Newark, Del., assignor to Hercules Incorporated, Wilmington, Del. N Drawing. Filed Aug. 7, 1968, Ser. No. 750,745 Int. Cl. C07c 73/00 U.S. Cl. 260-610 4 Claims ABSTRACT OF THE DISCLOSURE Peroxides of the formula CH3 "'(IJ'OOC(GHQ)J where R has the formula C H -C(CH CH3 I CHs- (5-CH5 are peroxides which cure polyethylene and other polymers and have odor-free, non-blooming and non-scorching properties.

CH3 CH3 i CH3CHCHa have the odor-free curing property of the bisperoxides and are non-blooming and non-scorching.

The peroxides of this invention have the formula EH3 CH3 CH3 l or CH3CHOH3 The preparation and use of the peroxides of this invention are illustrated by the following examples in which all parts and percentages are by weight.

where R is Patented June 8, 1971 EXAMPLE 1 p-Isopropyl-a-chloroisopropylbenzene was prepared by mixing 40 parts each of p-isopropenylisopropylbenzene and cumene and adding the mixture dropwise to 100 parts cumene saturated with dry hydrogen chloride at 0 C.; and after about an hour this mixture was added dropwise to a mixture of 1500 parts cumene, 8 parts aluminum chloride, and 10 parts nitromethane, and are maintained saturated with dry hydrogen chloride at 0 C. for one hour. The reaction was terminated by adding water, separating the acidic water and washing with 8% sodium hydroxide. The product was distilled to obtain 42.2 parts of a-phenyl-p-diisopropylbenzene RR 120- 130 C./0.95-0.85 torr. and the structure was verified by molecular weight and NMR analyses. Benzene and diisopropylbenzene were by-products of the reaction.

a-Phenyl a hydroxy-p-diisopropylbenzene was prepared by contacting 40.4 parts of u-phenyLp-diisopropylbenzene with oxygen at 115 C. while vigorously mixing with 50% sodium hydroxide for 8 hours. It was purified by countercurreut distribution between methanol and hexane.

a-t-Butylperoxya phenyl-p-diisopropylbenzene was prepared by mixing 12.7 parts a-phenyl-a'-hydroxy-p-diisopropylbenzene, 6.6 parts 82% t-butylhydroperoxide and 100 parts hexane refluxing to azeotropically remove water and then adding 0.25 part p-toluene sulfonic acid and continuing to reflux until no more Water evolved. The product amounting to 12.7 parts was 52.5% a-t-butylperoxy-a-phenyl-p-diisopropylbenzene as shown by iodometric peroxide analysis.

EXAMPLE 2 4- l-methylcyclohexyl) isopropylbenzene was prepared by reacting 120 parts cumene with 96 parts l-methylcyclohexene in the presence of 166 parts 96% sulfuric acid for 1.25 hours at 510 C. The reaction mixture was washed with water and aqueous sodium hydroxide and then distilled. The fraction boiling at 124129 C. (3.44.9 torr.), amounting to 133 parts was the desired product.

4-(1-methylcyclohexyl) a hydroxyisopropylbenzene was prepared by oxidizing 4-(l-methylcyclohexyl)isopropylbenzene as in Example 1.

4-(1-methylcyclo) a t butylperoxyisopropylbenzene was prepared by reaction 69.6 parts 4(1-methyl cyclohexyl)-a-hydroxyisopropylbenzene with 32.4 parts 82% t-butylhydroperoxide in parts heptane using 0.57 part p-toluenesulfonic acid in 2 ml. water as the catalyst. The reaction was carried out as in Example 1 using azeotropic distillation for removal of water. The desired peroxy compound obtained amounted to 82.4 parts and was 57.4% pure as determined by iodometric analysis for peroxide content.

EXAMPLE 3 4-(1-methyl 4 isopropylcyclohexyl)isopropylbenzene was prepared by reacting 120 parts cumene with 97.4 parts carvomenthene in the presence of 156 parts 96% sulfuric acid for 1.25 hours at 5-10 C. as in Example 1. There was obtained 112.6 parts of distilled product of which 62.4% was the above named isomer and 37.6% was the isomers thereof.

4 (l-methyl-4-isopropylcyclohexyl)-ahydroxyisopropylbenzene was prepared by contacting parts of 4-(1 methyl-4-isopropylcyclohexyl)isopropylbenzene in admixture with its isomers with 50 parts 50% sodium hydroxide and oxygen while agitating vigorously for about 12 hours at -117" C. The 4-(1-methyl-4-isopropylcyclohexyl)-a-hydroxyisopropylbenzene was separated by countercurrent distribution between hexane and acetonitrile from the hydrocarbon fraction as a crystalline mix- 60% propylene) 70 parts carbon black, parts oxide and ture of isomers which was not further purified. 0.5 part AgeRite Resin D antioxidant, and then incorpo- 4-(1-methyl-4-isopropylcyclohexyl) (a-t-butylperoxyrating 5 parts of peroxide to act as a curing agent. The isopropyl) benzene Was prepared by reacting 19.17 parts peroxides used were: 4-(1-methyl-4 isopropylcyclohexyl) (u-hydroxyisopro- 5 b pyl) benzene, with 25 parts t-butylhydroperoxide in 80 F Example 1 Percent pure yperoxlde g parts heptane containing 0.25 part p-toluenesulfonic acid G Example 2 catalyst by the method used 1n Example 1. The product H m bis(wbbutylperoxyisopropyl) benzene 100 amounting to 20.6 parts was a crystalline mixture of isomers which was shown by iodometric analysis for peroxides to be 80.1% peroxides of the designated formula.

The compositions were tested on the Monsanto oscillating disk rheometer. This rheometer is a device which measures dynamic properties, curing and processing char- CURING EXAMPLES acteristics of elastomer compositions during the curing cycle. In the test a sample is placed in the device and Samples of unfilled and black-filled P P 3" a disk embedded in the sample was subjected to oscilethylene y) were P p and compounded a latory motion by a motor-driven eccentric wherein the With 10 and -9 P 0f the P of this invention, force (torque) required to oscillate the disk could be f P1111 antloxldant (AgeRlte Resin V measured electronically while heating at controlled tembllt C0. trademark for Polymeflzed tflmethyldlhydfoperatures. The tests were carried out at 330 F. with quinoline) f tW0'T11 mi11 at Thfi blackoscillation at 900 cycles per minute while following the filled COInpOSmOns contained 40 phr. carbon black. After torque measurements, The first torque measurement taken compounding and Sheeting Off the min, Samples Were was the minimum reached at initial equilibrium before placed in a 254 X 1.27 X -1891 0111- pi re frame mold cure began, T-min. Subsequent torque measurements were and cured at 177 C. for 10 minutes, and another Sample taken at intervals of time so as to be able to plot a was cured at 188 C. for 10 minutes. The gel-swell values curve of torque against time. The test was stopped after for each composition were determined by immersing the a maximum was reached. Pertinent data are reported sample in xylene at 110 C, for 16 hours, and then dein Table 3.

TABLE 3.EPM CURE DATA (165.5 0.)

Torque, Scorch Torque, Cure Peroxide minimum Time time* Tao two T05 1505* maximum life rate Example I 30.4 2.1 3.2 48.1 18.4 49 22.1 50 4.5 15.2 Example II 30, 6 1. 9 3. 2 43. 9 16. 7 44. 7 18. 8 45. 4 4. 3 12. 5 S890 100% M. 33. 7 1. 8 2. 8 45. 3 17 T05 20. 7 46. 6 5. 0 14.2

Time in minutes. termining the gel and swell. The data are tabulated in Besides polyethylene, the following polymers are cured Tables 1 and 2. The peroxides used are: by the peroxides of this invention when compounded by the above procedure, or by known processes particularly Percent pure by per ide an lysi adapted to the particular polymer: natural rubber poly- A-Example 1 2. isoprene, cis-4-polybutadiene, poly(chloroprene), poly- -B-Example 2 57. styrene, silicone rubber, -EPM, EPDM, SBR, NBR and CExample 3 30.1 mixtures of said polymers. D-Bis(a-t-butylperoxyisopropyl) benzene 92.0 The amount of composition used in compounding with E-Dicumyl peroxide 90.0 the polymer is usually in the range of from about 0.1%

TABLE 1.UNF1LLED COMPOSITIONS Peroxide Equiva- Weight, phr. Milli- Gel (swell) results (percent) lent equiv., weight Gross Corrected phr. 177 C. cure 1 188 C. cure 1 1 10 minute cure. Z 7 minute cure.

TABLE 2.CARBON BLACK-FILLED Peroxide Equiva- Weight, phr. Milli- Gel (swell) results (percent) lent equiv., weight Gross Corrected phr. 177 C. cure 1 188 C. cure I 1 10 minute cure. 2 7 minute cure. 3 80 phr. carbon black.

EPM compositions were prepared by milling parts to about 5% phr., in an amount sufficient for the desired ethylene-propylene copolymer (4046% ethylene54- 75 degree of cross-linking. The compounding can be carried out in any of the well-known milling or mixing devices known to the art, or the peroxide can be coated on the surface of the compounded rubber using a solvent solution of the peroxide. The polymer can be thus compounded in thin sheets with the peroxide added last. The polymer can be filled with the usual rubber fillers, or it can be unfilled.

The curing process is accomplished by heating at a temperature in the range of 130 C. to 200 C. for a time suflicient to effect the desired cure. During cure, the polymer composition can be held in a shaping mold, or it can be pre-shaped and cured outside a mold.

What I claim and desire to protect by Letters Patent 1. A peroxide of the formula 2. A peroxide of claim 1 in which R is 3. A peroxide of claim 1 in which R is 4. A peroxide of claim 1 in which R is BERNARD HELFIN, Primary Examiner 30 W. B. LONE, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. U.S.P. 3,584 .057 D t d June 8, 1971 Inventor) Frederick G. Schappell (Case 2) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1, between line 19 and 27 of p.p.; Page 1, Line 6-10 7 of spec.

CH3 CH3 S should be CH3-C-CH3 CH3-CH-CH3 Col 4, Line 1 of p.p. Page 8, Line 3 of spec.

"parts oxide" should read "parts zinc oxide" Signed and sealed this 26th day of October 1971.

(SEAL) Attest:

ROBESRT GOTTSCHALK EDWARD M-FLE'ICHER, JR.

Acting, Commissioner of Patents Attestinpg Officer 

